public class _13a2振兴中华 {
    public static void main(String[] args) {
        int ans = fun(0,0);
        System.out.println(ans);
    }
    public static int fun(int i,int j){
        if(i==3||j==4){
            return 1;
        }
        return fun(i+1,j)+fun(i, j+1);
    }
}
